Translating power adjustable steering column with geared rack for an absolute sensor

ABSTRACT

An axially adjustable steering column assembly includes an upper jacket. The steering column assembly also includes a lower jacket, wherein the upper jacket is received within the lower jacket and is telescopingly adjustable therein, the lower jacket defining a pair of slots extending in an axial direction of the lower jacket. The steering column assembly further includes a column mounting bracket, wherein the lower jacket translates and rotates relative to the column mounting bracket. The steering column assembly yet further includes a pair of bushings positioned within the pair of slots. The steering column assembly also includes a geared rack operatively coupled to one of the pair of bushings, the geared rack correspondingly rotatable with the lower jacket. The steering column assembly further includes a sensor in operative contact with the geared rack to detect the axial position of the axially adjustable steering column assembly.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefits of priority to U.S. PatentApplication Ser. No. 63/388,298, filed Jul. 12, 2022, the disclosure ofwhich is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The embodiments described herein relate to vehicle steering systems and,more particularly, to a translating power adjustable steering columnwith a geared rack for an absolute sensor.

BACKGROUND

A vehicle, such as a car, truck, sport utility vehicle, crossover,mini-van, marine craft, aircraft, all-terrain vehicle, recreationalvehicle, or other suitable vehicles, include various steering systemschemes, for example, steer-by-wire and driver interface steering. Thesesteering system schemes typically include a steering column fortranslating steering input to an output that interacts with a steeringlinkage to ultimately cause the vehicle wheels (or other elements) toturn the vehicle.

Some steering columns are axially adjustable between positions. In thepast, a function of axially adjustable steering columns was to provideflexibility in the location of the hand wheel and facilitate morecomfortable driving positions for different sizes of drivers. However,now there are opportunities for significantly more telescopic travel,which also may be referred to as stow travel (i.e., when the hand wheelis not needed). For example, the hand wheel could be repositionedfurther away from the driver to allow him or her to do things other thanoperate the vehicle, such as work on a laptop computer when the vehicleis parked. Other examples include vehicles with autonomous drivingcapability, such that the hand wheel could be stowed when the vehicle isin an autonomous driving mode.

As the automotive industry increasingly heads toward steer-by-wiretechnologies, more emphasis is being placed on redundancies in positionsensing technologies for guarantee of comfort component locations duringfunctional and stow modes. As such, some OEMs may request the use ofdirect, absolute sensing of steering column telescope position, incontrast with prior reliance upon encoders and Hall-Pulse analysis.Absolute position sensing requires that the sensor be able to physicallyread the position of the steering column's telescope position. For anexternally translating, internally telescoping column, the columnassembly has two distinct interfaces that may move simultaneously duringa stow function. The first movement is upper jacket movement in relationto the lower jacket (i.e., typical of standard power telescopeadjustable columns), but this movement is also paired with a secondtranslating interface between the lower jacket and a column mountingbracket. These two motions together create a high stow rate and largestow displacement in the vehicle that shuttles the handwheel toward andinto the instrument panel.

Standard telescope sensing systems with an absolute position sensorinvolves a geared rack that is driven by the motion of the upper jacket.This geared rack runs along the absolute position sensor, which in turndrives cogged wheels on the sensor. The rotational motion of the coggedwheels is then used to account for the position of the upper jacket inits telescope motion. This externally translating, internallytelescoping column poses a challenge regarding how to use an absoluteposition sensor to sense the displacement of the lower jacket relativeto the column mounting bracket. This is because the stowing motion onlymoves in one plane (i.e., fore/aft in vehicle), while the lower jacketcan also articulate vertically during a rake function. This causes aunique situation requiring special considerations as to how a gearedrack can be implemented to interface with the absolute position sensor.The geared rack must be fixed in position to the column mountingbracket, but must also be able to articulate with the rake motions ofthe lower jacket.

SUMMARY

According to one aspect of the disclosure, an axially adjustablesteering column assembly includes an upper jacket. The steering columnassembly also includes a lower jacket, wherein the upper jacket isreceived within the lower jacket and is telecopingly adjustable therein,the lower jacket defining a pair of slots extending in an axialdirection of the lower jacket. The steering column assembly furtherincludes a column mounting bracket, wherein the lower jacket translatesand rotates relative to the column mounting bracket. The steering columnassembly yet further includes a pair of bushings positioned within thepair of slots. The steering column assembly also includes a geared rackoperatively coupled to one of the pair of bushings, the geared rackcorrespondingly rotatable with the lower jacket. The steering columnassembly further includes a sensor in operative contact with the gearedrack to detect the axial position of the axially adjustable steeringcolumn assembly.

According to another aspect of the disclosure, an axial position sensingsystem for a steering column assembly includes a column mountingbracket. The axial position sensing system also includes a columnstructure operatively coupled to the column mounting bracket, the columnstructure moveable in an axial direction relative to the column mountingbracket and rotatable relative to the column mounting bracket, thecolumn structure defining a pair of slots extending in an axialdirection of the column structure. The axial position sensing systemfurther includes a pair of wedge bushings positioned within the pair ofslots, the wedge bushings have at least one tapered surface disposed incontact with one or more walls defining the pair of slots. The axialposition sensing system yet further includes a geared rack integrallyformed with one of the pair of wedge bushings. The axial positionsensing system also includes a sensor in operative contact with thegeared rack to detect the axial position of the column structure.

These and other advantages and features will become more apparent fromthe following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter that is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features, and advantages ofthe invention are apparent from the following detailed description takenin conjunction with the accompanying drawings in which:

FIG. 1 schematically illustrates a vehicle steering system;

FIG. 2 is an elevation view of a steering column assembly for thevehicle steering system in a first rake position;

FIG. 3 is an elevation view of the steering column assembly in a secondrake position;

FIG. 4 is an elevation view of the steering column assembly in anaxially stowed position;

FIG. 5 is a perspective view of the steering column assemblyillustrating a geared rack; and

FIG. 6 is a perspective view of the steering column assemblyillustrating the geared rack in contact with an absolute positionsensor.

DETAILED DESCRIPTION

The following discussion is directed to various embodiments of thedisclosure. Although one or more of these embodiments may be describedin more detail than others, the embodiments disclosed should not beinterpreted, or otherwise used, as limiting the scope of the disclosure,including the claims. In addition, one skilled in the art willunderstand that the following description has broad application, and thediscussion of any embodiment is meant only to be exemplary of thatembodiment.

As described, a vehicle, such as a car, truck, sport utility vehicle,crossover, mini-van, marine craft, aircraft, all-terrain vehicle,recreational vehicle, or other suitable vehicles, include varioussteering system schemes, for example, steer-by-wire and driver interfacesteering. These steering system schemes typically include a steeringcolumn for translating steering input to an output that interacts with asteering linkage to ultimately cause the vehicle wheels (or otherelements) to turn the vehicle. Some steering columns are axiallyadjustable between positions. In the past, a function of axiallyadjustable steering columns was to provide flexibility in the locationof the hand wheel and facilitate more comfortable driving positions fordifferent sizes of drivers. However, there are now opportunities forsignificantly more axial travel, which also may be referred to as stowtravel (i.e., when the hand wheel is not needed). For example, the handwheel could be repositioned completely away from the driver to allow himor her to do things other than operate the vehicle, such as work on alaptop computer when the vehicle is parked. Other examples includevehicles with autonomous driving capability, such that the hand wheelcould be stowed when the vehicle is in an autonomous driving mode.

Referring now to the drawings, where the various embodiments are shownand described herein, without limiting same, the Figures illustrateembodiments of a steering column assembly that is axially adjustablewith improved packaging and other operational benefits. The axialadjustability results from relative movement between two or moresteering column portions (e.g. jackets, brackets, rails, and/or thelike) that permit axial movement therebetween, in combination withrelative movement between multiple steering shaft portions which permitaxial movement therebetween. Axial movement refers to movement resultingfrom relative telescopic, sliding, or translational movement betweencomponents.

Referring initially to FIG. 1 , a vehicle 20 is generally illustratedaccording to the principles of the present disclosure. The vehicle 20may include any suitable vehicle, such as a car, a truck, a sportutility vehicle, a mini-van, a crossover, any other passenger vehicle,any suitable commercial vehicle, or any other suitable vehicle. Whilethe vehicle 20 may be a passenger vehicle having wheels and for use onroads, the principles of the present disclosure may apply to othervehicles, such as planes, tractors, boats, or other vehicles. Thevehicle 20 may include a propulsion system 30, such as an ignitionsystem, an electronic system, or combinations thereof.

The vehicle 20 further includes a steering system 40. The steeringsystem 40 may be configured as a driver interface steering system, anautonomous driving system, or a system that allows for both driverinterface and autonomous steering. The steering system 40 may include aninput device 42, such as a steering wheel, wherein a driver maymechanically provide a steering input by turning the steering wheel. Asteering column assembly 44 includes a steering column 45 that extendsalong an axis from the input device 42 to an output assembly 46. Theoutput assembly 46 may include a pinion shaft assembly, an I-shaft, acardan joint, steer-by-wire components or any feature conventionallylocated opposite the input device 42.

The steering column 45 may include at least two axially adjustableportions, for example, an upper jacket 48 and a lower jacket 50 that areaxially adjustable with respect to one another. The at least two axiallyadjustable portions may further include at least one third portion 49that is disposed between the upper jacket 48 and the lower jacket 50 insome embodiments. It is to be appreciated that other structural featuresof the steering column 45 may be part of the upper jacket 48 and thelower jacket 50, such as brackets, rails, other devices, or combinationsthereof.

The steering column 45 is moveable over a range of positions from afully extended position to a fully retracted position. In the fullyextended position, the upper jacket 48 and the lower jacket 50 are movedaxially so that the input device 42 is located near an operator of thevehicle. In the retracted position, the upper jacket 48 and the lowerjacket 50 are moved axially so that the input device 42 is locatedfurther away from an operator of the vehicle, when compared to theextended position. In some embodiments, the retracted position maycorrespond to stowing the input device 42. For example, it may bebeneficial to place the input device 42 in a stowed location duringautonomous driving. In operation, the axial movement of the upper jacket48 and the lower jacket 50 may be effectuated by manual movement by anoperator or electromechanically by a telescope actuator. This axialmovement adjusts between the extended position, the retracted position,and any intermediary positions.

A steering gear assembly 54 may connect to the output assembly 46 via asteering gear input shaft 56. The steering gear assembly 54 may beconfigured as a rack-and-pinion, a recirculating ball-type steeringgear, or any other types of steering gears associated with autonomousand driver-interface steering systems. The steering gear assembly 54 maythen connect to a driving axle 58 via an output shaft 60. The outputshaft 60 may include a pitman arm and sector gear and/or varioustraditional components. The output shaft 60 is operably connected to thesteering gear assembly 54 such that a rotation of the steering gearinput shaft 56 causes a responsive movement of the output shaft 60 andcauses the drive axle to turn wheels 62. It is to be appreciated thatthe steering components described herein may be part of a steer-by-wiresystem or one which includes a direct mechanical linkage over the spanof the components.

With reference now to FIGS. 2 and 3 , the steering column assembly 44 isillustrated in greater detail. The upper jacket 48 is shown protrudingfrom the lower jacket 50. The lower jacket 50 is operatively coupled to,and axially translatable relative to, a column mounting bracket 70. Thecolumn mounting bracket 70 is fixed relative to a vehicle structure tomount the steering column assembly 44 to the vehicle 20. The upperjacket 48 is axially adjustable relative to the lower jacket 50 over afirst range of axial positions which may be referred to as a “comfortrange”. The comfort range is a range of axial positions that are usefulfor manual driving during operation of the vehicle for different sizedoperators. The axial movement of the upper jacket 48 relative to thelower jacket 50 is done in a telescoping manner due to the movement ofthe upper jacket 48 within the lower jacket 50. The comfort rangeencompasses the entire comfort range and possibly a portion of thestowing range. The lower jacket 50 is axially adjustable relative to thecolumn mounting bracket 70 over a second range of axial positions whichmay be referred to as a “stowing range”. The stowing range is a range ofaxial positions that moves the overall steering column assembly 44further away from the operator when compared to the comfort range. Insome embodiments, the fully retracted position is a stowed position thatmay result in the steering input device (e.g., steering wheel) beingflush with an instrument panel, firewall or other vehicle structure. Theaxial movement of the lower jacket 50 relative to the column mountingbracket 70 is done in a translating manner due to the movement of theoverall upper and lower jackets together adjacent to the column mountingbracket 70. FIG. 4 illustrates the axial stowing adjustability of thesteering column assembly 44, with the first portion 48 fully retractedwithin the second portion 50 and with the second portion fullyretractably translated, relative to the column mounting bracket 70.

The steering column assembly 44 includes a first actuator 72 which maybe referred to as a comfort actuator. The first actuator 72 isoperatively coupled to the upper jacket 48 to control the telescopingmovement of the upper jacket 48 relative to the lower jacket 50 over thefirst range of axial positions. In the illustrated embodiment, the firstactuator 72 is mounted to a specific portion of the steering columnassembly 44, but other mounting locations are contemplated.

The steering column assembly 44 also includes a second actuator 74 whichmay be referred to as a stowing actuator. The second actuator 74 isoperatively coupled to the lower jacket 50 to control the translatingmovement of the lower jacket 50 relative to the column mounting bracket70 over the second range of axial positions. In the illustratedembodiment, the second actuator 74 is mounted to a specific portion ofthe steering column assembly 44, but other mounting locations arecontemplated.

Both the first and second actuators 72, 74 are located proximate aforward location of the steering column assembly 44 to accommodate theaxial movement during a stowing operation. The two actuators 72, 74 areresponsible for the full stow motion of the column, however only thefirst actuator 72 operates during comfort adjustment within the firstrange of axial adjustment positions.

With continued reference to FIGS. 2 and 3 , in addition to the axialadjustability of the steering column assembly 44, the steering columnassembly 44 is adjustable in a rake direction which allows angulararticulation of the overall steering column assembly 44 about a pivotaxis that the lower jacket 50 rotates about. This effectively allowsupward or downward movement of the steering input device 42 for a user'spreference. A rake actuator assembly 76 is mounted to the lower jacket50. As shown, the lower jacket 50, and therefore the steering columnassembly 44, moves between various rake positions, including a firstrake position (FIG. 2 ) and a lowered, second rake position (FIG. 3 ).It is to be understood that different ranges of rake adjustability willbe employed for different steering column applications of use.

As shown in FIG. 5 , the embodiments disclosed herein include taperedrail slots 80 defined within the lower jacket 50, which form a pair oftracks. In particular, a first track is formed on one side of the lowerjacket 50 by one of the slots and a second track is formed on a secondside of the lower jacket 50. At least one sliding wedge bushing 84 isdisposed within each of the tapered rail slots 80. The sliding wedgebushings 84 have a tapered shape that substantially corresponds to theangled orientation of the tapered rail slots 80. The tapered rail slots80 in each component serve as a receiving interface for the de-lashingsliding wedge bushings 84 and provide guidance for the lower jacket 50to translate relative to the column mounting bracket 70 during stowoperation.

A geared rack 90 is coupled to one or more wedge bushings 84 and engagesthe absolute position sensor 92. The geared rack 90 includes a surfacehaving a plurality of teeth 91 formed on at least a portion of thelength of the surface. Each geared rack is coupled to one or more of thewedge bushings 84 or is integrally formed with the wedge bushings 84 toform a single, unitary component. The geared rack 90 and the wedgebushings 84 are operatively coupled to the column mounting bracket 70.Therefore, the geared rack 90 and the wedge bushings 84 remainstationary relative to the lower jacket 50 during translation of thelower jacket. However, the geared rack 90 and the wedge bushings 84 arecoupled to the column mounting bracket 70 in a pivotable manner. Assuch, during rake articulation of the lower jacket 50, the wedgebushings 84 remain aligned with their respective tracks of the lowerjacket 50 to allow guided translation of the lower jacket 50.

For the translating function of the stow motion, an absolute positionsensor 92 is mounted to the lower jacket 50 (FIG. 6 ). As the lowerjacket 50 goes through its rake articulations, the wedge bushings 84follow the articulations, keeping the geared rack in alignment with anabsolute position sensor 92 that is fixed to the lower jacket 50.However, as the steering column assembly 44 moves into stow function,the wedge bushings 84—fixed positionally to the lower jacket 50—remainin place with the column mounting bracket 70 as the lower jacket 50translates relative to the column mounting bracket 70 and the gearedrack 90.

Referring to FIG. 6 , as the lower jacket 50 translates, the pluralityof teeth 91 of the geared rack 90 runs along cogged teeth 93 of theabsolute position sensor 92, providing for an accurate account of theaxial position of the steering column assembly 44, without being skewedduring different rake positions of the lower jacket 50.

While the invention has been described in detail in connection with onlya limited number of embodiments, it is to be readily understood that theinvention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Moreover, any feature,element, component or advantage of any one embodiment can be used on anyof the other embodiments. Accordingly, the invention is not to be seenas limited by the foregoing description.

What is claimed is:
 1. An axially adjustable steering column assemblycomprising: an upper jacket; a lower jacket, wherein the upper jacket isreceived within the lower jacket and is telecopingly adjustable therein,the lower jacket defining a pair of slots extending in an axialdirection of the lower jacket; a column mounting bracket, wherein thelower jacket translates and rotates relative to the column mountingbracket; a pair of bushings positioned within the pair of slots; ageared rack operatively coupled to one of the pair of bushings, thegeared rack correspondingly rotatable with the lower jacket; and asensor in operative contact with the geared rack to detect the axialposition of the axially adjustable steering column assembly.
 2. Theaxially adjustable steering column assembly of claim 1, wherein each ofthe pair of bushings have at least one tapered surface disposed incontact with one or more walls defining the pair of slots.
 3. Theaxially adjustable steering column assembly of claim 2, wherein the oneor more walls of the pair of slots are tapered to correspond to the atleast one tapered surface of the pair of bushings.
 4. The axiallyadjustable steering column assembly of claim 1, wherein the geared rackis integrally formed with the one of the pair of bushings.
 5. Theaxially adjustable steering column assembly of claim 4, wherein thegeared rack is operatively coupled to the column mounting bracket and ispivotable relative to the column mounting bracket.
 6. The axiallyadjustable steering column assembly of claim 1, wherein the geared rackincludes a plurality of rack teeth, the sensor comprising an absoluteposition sensor having a toothed wheel in contact with the plurality ofrack teeth.
 7. The axially adjustable steering column assembly of claim6, wherein the toothed wheel is one of a plurality of toothed wheels ofthe absolute position sensor.
 8. The axially adjustable steering columnassembly of claim 1, wherein the geared rack does not translate relativeto the column mounting bracket.
 9. The axially adjustable steeringcolumn assembly of claim 1, further comprising: a first actuatoroperatively coupled to the upper jacket to control axial adjustment ofthe upper jacket relative to the lower jacket; a second actuatoroperatively coupled to the lower jacket to control axial adjustment ofthe lower jacket relative to the column mounting bracket; and a rakeactuator operatively coupled to the lower jacket to control rakeadjustment of the lower jacket.
 10. An axial position sensing system fora steering column assembly comprising: a column mounting bracket; acolumn structure operatively coupled to the column mounting bracket, thecolumn structure moveable in an axial direction relative to the columnmounting bracket and rotatable relative to the column mounting bracket,the column structure defining a pair of slots extending in an axialdirection of the column structure; a pair of wedge bushings positionedwithin the pair of slots, the wedge bushings have at least one taperedsurface disposed in contact with one or more walls defining the pair ofslots; a geared rack integrally formed with one of the pair of wedgebushings; and a sensor in operative contact with the geared rack todetect the axial position of the column structure.
 11. The axialposition sensing system of claim 10, wherein the one or more walls ofthe pair of slots are tapered to correspond to the at least one taperedsurface of the pair of wedge bushings.
 12. The axial position sensingsystem of claim 10, wherein the geared rack is operatively coupled tothe column mounting bracket and is pivotable relative to the columnmounting bracket.
 13. The axial position sensing system of claim 10,wherein the geared rack includes a plurality of rack teeth, the sensorcomprising an absolute position sensor having a toothed wheel in contactwith the plurality of rack teeth.
 14. The axial position sensing systemof claim 13, wherein the toothed wheel is one of a plurality of toothedwheels of the absolute position sensor.
 15. The axial position sensingsystem of claim 10, wherein the geared rack does not translate relativeto the column mounting bracket.